With advancements in Flex Fuel technology, the use of ethanol for ICE has increased in the past few years. This means lower cost in comparison with the use of gasoline or diesel fuels and also a benefit to the environment when the results of discharge gas emissions are analyzed. However, automotive engines operating with ethanol have ignition difficulties when the temperature is below 15° C. due to the ethanol vaporization pressure be very low and its flash point be higher than operating with gasoline. For this reason, current systems have a secondary tank (202) containing gasoline which is used to start engine when its temperature is below 15° C., as seen on FIG. 1. As schematically represented in FIG. 1, this start up system comprises a reservoir (202), a supply pump (205) with adequate gasoline flow, feeding pipes (207) to a gasoline dosage valve (206), a mini fuel rail (203) required to supply dosed gasoline to the pipes of the intake manifold, calibrated-roles inserts (204) for an appropriate spraying of gasoline into the cylinders, and an engine intake manifold (201).
In Brazilian patent PI 0504015-9 by Márcio Turra de Ávila and Marcelo Valente Feitosa, the solution found for cold ignition was the use of an independent system, provided with a heating coil, and the use of an injector (or fuel injector, or atomizer) for the secondary fuel. With that solution, the number of fuel injectors to inject gasoline into the intake manifold or engine will always be a multiple of the number of fuel injectors used for ethanol injection. In this kind of solution, the problem is the high cost of the system due to the use of two fuel injectors, one for cold ignition of gasoline and another for the normal operation of the engine, for each engine cylinder.
Brazilian patent PI 0703443 by Ademar Rudge Filho discloses a solution using a system with a fuel rail to distribute fuel for cold ignition to the injector, wherein there is an exclusive injector for cold ignition for each engine cylinder. The great disadvantage of this system is the high cost due to the use of an additional injector for each engine cylinder solely dedicated to the cold ignition of the engine at low temperature.
Brazilian patent PI 0705422-0 by Gino Montanari et al discloses a tube device of heat diffusion passive regulation connected to one or more heating devices and inserted into a fuel supply primary rail in an ethanol cold start system.
Brazilian patent MU 8403382-7 by Eduardo Augusto de Campos discloses a controlled heating device for the body of the main fuel injector, reporting that it has great technical and functional advantages over conventional ignition systems with gasoline.
Brazilian patents PI 0403039-7 and P040104172 by Eduardo Augusto de Campos disclose the whole strategy of the ethanol cold start system, reporting the concept of the utilization of a heating device for fluid fuel which is activated by a signal coming from a sensor installed on the vehicle door or another kind of signal. The device object of this patent application is an integrant part of the invention strategy disclosed. The author, Eduardo Augusto de Campos, also discloses in Brazilian patents PI0405182 and PI 0405181, possible configurations to heat the fluid fuel of the cold start system.
Brazilian patent PI 0805484-3 by Akio Omori et al discloses the way of axial installation of heating devices in a primary fuel supply rail of the no-return kind, which increases the homogeneity of the heat flow in a cold start system with ethanol ECS®. The device object of this patent application, is an integrant part of this invention disclosed.
The heating device assembled inside the fuel rail is designed to transform electric energy into thermal energy (Joule effect) transferring its heating potential to the fuel present inside the chamber to be later transported heated and to be sprayed to engine cylinders by fuel injectors.
U.S. Patent Application Publication No. 2009/0308362.A1 by Jens Schneider et al discloses a heater whose resistance element is in a powder composed of insulating and refractory material, which is inserted into a metal tube shaped to compress the powder on the resistance element. Other devices with similar functions have already been patented and manufactured by several corporations, both in Brazil and abroad, but they do not have the safety feature (fuse effect) required to guarantee the integrity of the system in case of control failure in the electronic control unit (ECU). Said function is even more important in applications where fuel rails are made of polymeric materials.